A scanner can be of help on many late model cars to diagnose many body controls problems, but this year model is not equipped with a body module so dignosis will have to be done by consluting wireing diagram and test power and grounds. In this case if there is power at stop light swicth that power goes though turn signal switch then to rear stop/turn signals. The smtom of no brake kights and no signals makes the turn signal switch highly suspect.(in my opinion)